1. Field of the Invention
The present invention relates to a vehicular driving force distribution system comprising a torque distribution mechanism which includes a planetary gear mechanism and which is arranged between axles of left and right wheels, any two elements among three elements of the planetary gear mechanism being locked to a fixed portion via torque distribution clutches, respectively, so that torque is distributed between the axles of the left and right wheels.
2. Description of the Related Art
Such a vehicular driving force distribution system is disclosed in Japanese Patent Application Laid-open No. 8-114255. In this vehicular driving force distribution system, a torque transmission means comprising a planetary gear mechanism is provided between axles of right and left wheels, and torque is distributed between the right and left wheels by selectively restraining a sun gear or a carrier member of the planetary gear mechanism to forcibly control the rotational speed ratio between the right and left wheels.
If the differential of right and left axles is suppressed when a vehicle is running straight at a high speed, the straight line stability can be enhanced. Also in the vehicular driving force distribution system described in Japanese Patent Application Laid-open No. 8-114255, the right and left axles are integrated so as to be incapable of being relatively rotated by engaging a pair of clutches in a predetermined slip ratio, whereby the differential limitation function can be exerted. However, it is difficult to engage the paired clutches at the predetermined slip ratio with a high accuracy, and the control thereof is complicated to raise a problem of decreased response.